I'm pretty sure there is an ATM in Downtown Disney Market place which is nearby.

There are definately ATM's in the Disney parks themselves as well.

There are lots of banks with ATM's all over Kissimmee and Lake Buena Vista. Most of them will be drive-thru's. but you will find them in Supermarkets too.
If I use an ATM that is outside my bank network I pay a fee of $2 plus my bank then charges me a fee for doing so- usually another $1.50- your bank can tell you which network to use and what the fees will be if any.

I have used my debit card in the UK without problem,at Lloyds Bank ATM's and stores and paid no fee,as long as I'm in the network.